


Fireflies

by elliex



Series: Destiel Smut Brigade Summer Challenge Fic Dump [16]
Category: Supernatural
Genre: Arguments, Cas communes with nature, Dean learns to use his words, Explicit Sexual Content, Fireflies, Human Castiel, I'm still working through S10 issues, M/M, Naked in the Moonlight, Post Mark of Cain Dean, Shipper Sam is fed up, Sick Sam, s10 spoilers, so this is kind of a fix-it (sort of)
Language: English
Status: Completed
Published: 2015-07-11
Updated: 2015-07-11
Packaged: 2018-04-08 18:51:57
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,958
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4315845
Author URL: https://archiveofourown.org/users/elliex/pseuds/elliex
Summary: <blockquote class="userstuff">
              <p>Dean and Castiel have dealt with a lot - The Mark of Cain, The Darkness, etc. - but can they deal with Castiel being human? </p><p>Dean's overprotective, and Castiel's not having it. Sam's sick with a cold and sick of Dean sabotaging his relationship. Can a beautiful summer night set the stage for Dean to get it together?</p>
            </blockquote>





	Fireflies

+

 

Dean wearily trudged along the hallway connecting the garage to the bunker. He shrugged to adjust his heavy duffle and ignored how the strap dug into his shoulder.

 

Normally, Dean came home from a salt and burn completely jazzed and raring to go. This time, though… well, things were different.

 

Dean huffed at himself, the sound echoing in the silence-shrouded hallway. _Things_ weren’t different: _Castiel_ was different. He’d wanted to come on the hunt since Sam was down with a nasty head cold, but Dean had quashed that idea immediately. It was bad enough that Castiel was human now and that it was all Dean’s fault. He didn’t need to fail Cas again, to let him get hurt – or even worse.

 

Dean opened the door to his bedroom, freezing when he saw that everything was exactly as he’d left it three days ago. He dropped his duffel to the floor with a loud thud and tried not to panic. In all his moping and grousing, he’d never thought he’d come back to this.

 

Dean forced himself to walk directly to the closet, but his hand hovered hesitantly over the doorknob. He steeled himself and yanked the door open. “Oh, thank God,” he said, scanning the familiar mix of suits, jeans, flannels, pull-overs, and button-ups – half his, half Cas’s.

 

Relieved, Dean looked around the room, but he felt distinctly unsettled as he noticed that there was no other evidence of Castiel’s recent presence. The book Dean had been reading still lay on the bed; two coffee cups still sat primly in their saucers beside Cas’s favorite (and empty) French press; the clothes hamper was full, though Cas liked to do laundry every Friday.  Dean’s heart clenched, and he had an awful idea: What if Castiel had left everything behind?

 

Dean’s rather panicked reconnaissance of the bunker only turned up Sam in the research room, wrapped in an afghan and surrounded by books. Dean wondered if his brother knew about the fight and tried to gauge how to approach asking about Cas.

 

When Sam looked up to deliver an epic bitchface made ten times more annoying by the feverish glint in his eyes, Dean scrubbed a hand over his face. Oh yeah, Sam knew _._

 

“ _Really_?,” Sam asked.

 

“Don’t start,” Dean snapped. “Where is he?”

 

Sam shrugged.

 

Dean grit his teeth. “I’m only asking one more time, Sam: Where is Castiel?”

 

“I. Don’t. Know,” Sam replied evenly.

 

The nasal tone to Sam’s voice undermined his cutting tone, but Dean still bristled. Before Dean could retort something extremely witty, Sam blurted out, “Seriously, Dean – Why can’t you accept whatever’s between you and Cas? Don’t realize that the two of you could be so happy if you’d only get your head out of your ass?”

 

Dean snorted in disbelief but shuffled uncomfortably under Sam’s scrutinizing gaze. He chose not to say anything, though, and after an awkward, silent minute, Sam sighed heavily.

 

“He went out,” Sam said.

 

Dean’s brow furrowed. “But his car’s in the garage.”

 

“No, not _out_ out. He took a backpack and a sleeping bag and left through the front door about three hours ago.”

 

“Thanks, Sammy,” Dean said quietly. He paused. “Um…Where’s he been sleeping?”

 

Sam pointedly refused to look at Dean, opening another book and dramatically scanning the page. “I’m not telling you anything else. Go talk to your husband.”

 

Dean was startled by Sam’s bluntness, but he tried to recover gamely. “Oh, come on, Sam,” he protested. “Isn’t that jumping the gun? I mean – he hasn’t even asked me to go steady –”

 

Sam glared. “Don’t even. He confronted a pissed-off Death for you, _and_ he used up his grace to create a new lock for the Darkness so that you wouldn’t have to bear the Mark for eternity.” Dean rubbed his forearm self-consciously as Sam talked; sometimes, Dean could still feel the burning hot tendrils of rage and murder spiking through his system. “He _saved_ you, Dean. For like the millionth time. And do you know why?”

 

Dean stared at his hands uncomfortably. “Don’t,” he muttered.

 

“Because he lov-_”

 

Dean’s head snapped up; this time, it was his turn to glare. “I said _don’t_.”

 

“Fine,” Sam snapped back. “You know it’s true, though. The question is, do you love him?”

 

“Don’t ask stupid questions,” Dean growled.

 

Sam’s face contorted pissily. “Then go tell him, numb nuts. And this time? Don’t flip out in a rage over something stupid.”

 

Dean scowled and proceeded to stomp loudly up the metal stairs, not caring one iota that each angry step thundered through the bunker.

 

If he’d looked back, he would have seen Sam watching him with a satisfied smirk.

 

+

 

It was humid outside, and Dean stood in the drive trying to figure out where Cas might have gone. There were no footprints, and the tall grasses that lined the bank looked undisturbed. He also didn’t see the shine of a flashlight or the smoke of a fire.

 

Dean pursed his lips and scanned the landscape. An otherworldly cluster of fireflies had gathered at the top of the ridge about a mile away. He smiled smugly. “Bingo.”

 

He began to hike up the hill that helped protect the bunker from prying eyes. A full moon was rising, so he was able to pick his way through the grasses and avoid loose stones fairly easily. Halfway there, he slipped off his flannel overshirt and tied it around his waist. The cool evening breeze ruffled his hair as he worked his way up the ridge, an endeavor that forced him to abandon any pretense of stealth.

 

About twenty minutes later, Dean was standing at the edge of a clearing decorated with multitudes of fireflies. Castiel sat on a faded sleeping bag in the middle, his eyes closed and his head bowed as if in prayer. He looked ethereal…angelic, even. Dean’s silent observation filled him with sadness.

 

“Hello, Dean,” Castiel said without moving or opening his eyes.

 

Dean wiped away the tears stinging his eyes and cleared his throat to rid it of the lump currently stuck in his throat. “Hey Cas,” he replied thickly.

 

Castiel didn’t acknowledge Dean’s response. Dean noticed that Castiel was barefoot and decided it might be wise to follow suit. He slipped off his boots and socks and carefully set them at the clearing’s edge; for good measure, he left his flannel shirt on top of them.

 

Dean approached Castiel slowly, reveling in the feeling of soft grasses beneath his feet. He couldn’t recall when he’d last gone barefoot, and he enjoyed the feeling. He even paused long enough to wiggle his toes in the grass.

 

Then he realized that he, a former Knight of Hell, was giddy about going barefoot, and the weight he’d been carrying around ever since he took the damn Mark crashed back down on him. He looked at Castiel’s ramrod-straight back and felt as if the few remaining feet between them were a vast ocean.

 

The futility of everything overwhelmed him, and Dean abruptly turned to go back the way he’d come. He’d managed a single step when Castiel’s voice cut through the twilight: “Dean.”

 

It was more command than request, and Dean stopped and turned towards Castiel instinctively. “Cas – uh – maybe I should go,” he said haltingly.

 

Without opening his eyes, Castiel patted the space beside him on the bag. “Sit.”

 

Dean sighed and did what Cas asked, sitting cross-legged and laying his hands, palms down, on his knees. Their shoulders brushed, and Dean wanted to lean into the touch, but he refrained. His stomach churned, and he felt more anxious at this moment than he had facing down Cain.

 

Castiel still sat with his eyes closed and a serene expression on his face, yet he reached his right hand hand out and covered Dean’s left, slotting their fingers together. Something inside Dean unclenched at the touch, and he let himself enjoy the feeling of Castiel’s hand in his – warm skin, strong fingers, steady pulse. Their connection soothed the ragged edges of his tattered soul.  

 

Dean tightened his grip on Cas’s hand and waited patiently until Cas was done with… whatever he was doing. As Dean waited, his eyes roved over Castiel’s profile – the shock of messy dark hair, long lashes, defined jawline, kissable lips. Dean’s leisurely inspection quickly sparked twitches below the belt that were enough to make him question the wisdom of sitting cross-legged.

 

Castiel squeezed his hand warningly, as if to curtail Dean’s wandering thoughts, so Dean decided to watch the fireflies instead. They were out in full force tonight, and the effect was bewitching. The sight made him think of the summer when he was eight and Sam four. John had left them at a motel for several days, and they’d made their own fun, including playing in the field behind the run-down motel. Jan, the motel manager, had given Dean a couple of mason jars to catch lightning bugs with, and he’d been so excited – He and Sam had run around the field, capturing as many as they could. When they went to bed, they turned out all the lights and watched the twinkling bugs until they fell asleep. It had been magical.

 

But morning had brought heartache. Sam had woken first, and he’d shaken Dean awake, asking what was wrong with the bugs. It had taken Dean a minute or so to realize that without airholes, the bugs had died. Even thinking of it now made Dean feel sick. Sam had cried when Dean explained their mistake, and he’d cried more when Dean had solemnly read from the motel room’s Gideon bible as they’d flushed the bugs. Dean hadn’t allowed himself to cry; after all, the whole thing was his fault. And he’d promised himself that he’d never capture fireflies again. It was a promise he’d kept.

 

Or had he?

 

The pieces slotted together in Dean’s mind as easily as Castiel had slotted together their fingers. And he felt sick, just as he had that long-ago morning. Unlike then, though, Dean could make this right.

 

“Cas.”

 

Castiel ignored him.

 

“Cas, please,” Dean pleaded. He resisted wincing at the whine in his tone.

 

Castiel raised an eyebrow but still didn’t open his eyes. “What?”

 

“I get it now.”

 

Castiel opened his eyes now, blinking as if to clear them. “You get what now?”

 

“I understand. And I’m – I’m sorry.” Castiel turned toward him, and Dean met his gaze squarely, refusing to blanch under the careful scrutiny of those mesmerizing blue eyes.

 

“What do you understand?”

 

“That – that…” Dean trailed off, unsure of how to begin.

 

“Use your words, Dean.”

 

“I. Um. Okay. You’ve read me, right? You know my childhood memories?”

 

“Yes,” Castiel confirmed. “I learned them when I resurrected you.”

 

“Okay, then. Remember the time Sammy and I caught the fireflies in mason jars, and they all died?”

 

“Yes.” Castiel’s expression became quite somber. “You were so distressed, but still you consoled Sam, even though your own heart was broken.” Cas’s other hand touched Dean’s chest, gingerly resting over his heart. “You still have that tender spirit, you know.”

 

Dean snorted. “How can you even say that to the guy who tried to kill Death and unleashed the Darkness? Let alone everything else I’ve done?”

 

“Because you atone. Even now, you’re here to atone to me, to make amends. Correct?” Castiel raised that eyebrow again, and Dean nodded. He wondered if Castiel could feel his heart thumping nervously.

 

“So what do fireflies have to do with your new understanding?,” Castiel asked, redirecting Dean’s thoughts back to their original topic of conversation.

 

Dean cleared his throat. “I – um. I think I was suffocating you, like I did the fireflies when I was a kid. I thought they were so cool and beautiful, and I just wanted to keep them safe and with me forever – and I killed them instead.”

 

Castiel reached over with his left hand to cup Dean’s face, gently caressing Dean’s cheek with his thumb. “You didn’t kill me,” he said softly.

 

Dean’s eyes started stinging again, and this time, he couldn’t will the tears away. “I tried to,” he murmured, dropping his eyes even as a lone tear trickled down his face.

 

Castiel shook his head. “That was then, when you were under the Mark. I’m here, and I’m alive.”

 

“But you’re going to die now, Cas. Because of me – I took that from you. You were an angel, and now you’re _human_.

 

“No, Dean. You didn’t take my grace. I didn’t lose it. I _gave_ it.”

 

“But if we hadn’t released the Darkness, if I hadn’t tried to kill Death—”

 

Castiel cut him off. “It’s true that I might not have given my grace without good reason, which your choices provided.” Dean grimaced, and Castiel brushed his thumb across the twisted edge of Dean’s mouth. Dean hesitantly met his eyes and Castiel smiled. “But do you honestly think I would want to live for an eternity if you weren’t part of it?”

 

“Angels are immortal,” Dean chided. “Don’t try to tell me that –”

 

Castiel interrupted again. “Yes, I would have been immortal. I could have visited you in heaven, perhaps even gotten you shore leave to help with missions on earth. But did I want that, Dean?”

 

“I don’t know.”

 

“Ask me, then,” Castiel suggested, dropping his hand from Dean’s face.

 

“What did – do – you want, Castiel?”

 

“You.”

 

Dean’s breath caught in his throat. He saw the flicker of uncertainty in Castiel’s eyes, the steeling of his jaw. He should have known what was coming next, but Castiel’s next words still threw him for a loop.

 

“What do _you_ want, Dean?”

 

With those words, Dean felt the full enormity of this moment. _This_ was now or never, put up or shut up…

 

“You,” he answered, reaching for Castiel. “It’s always been you.”

 

Castiel allowed Dean to pull him close, and the light in his eyes matched the light Dean could feel in his soul – the soul he’d worried for so long that he’d lost, the one that Castiel had restored to him.

 

“Really?,” Castiel asked. Dean saw the tightness around Cas’s eyes, the little pucker between his brows that bespoke of doubt. Dean cursed himself for causing Cas’s unease, and he swore he’d make it up to him, starting now.

 

“From the moment you laid a hand on me in hell, I was yours, Cas.” Dean closed the distance between them, kissing Castiel gently on the lips. He’d intended to keep the kiss chaste, but when Castiel’s tongue flicked at the seam of his lips, Dean was undone.

 

Instinctively, he slid his fingers through Castiel’s hair, cupping the back of his head and deepening the kiss. This – _This_ – he had missed terribly these past few days. Cas’s hands slid up under his tee, splaying across his back, and Dean drew back just enough to pull the shirt off and toss it onto the grass. Cas’s shirt came off next, and then they were fumbling at each other’s jeans, unbuttoning, unzipping, and shrugging off.

 

Dean reached for Cas, kissing him lightly on the lips and leaning him back against the sleeping bag. Dean began working his way down smooth, tanned skin, and Cas worked his fingers through Dean’s hair, tightening his grip as Dean worked every button he knew. Dean laved his tongue over each nipple, down Cas’s abdomen, across his tattoo. He relished the sounds that Castiel was making, and he brought it to a head when he began mouthing across the taut fabric of Cas’s boxer briefs. As always, Dean loved how Cas smelled, how he tasted, and he took hold of Cas’s waistband… but then, he hesitated, unsure of how far they were going – how far they _should_ go.

 

Cas chose that moment to say his name, soft and low. Dean nearly whimpered when those familiar syllables dropped from his beloved’s mouth. Cas lifted his hips, allowing Dean to slide his boxers down and off. Dean took his own off for good measure too before maneuvering back on top of Castiel. He braced his hands on either side of Cas’s torso and kissed him hard and fast before sliding back down and picking up where he’d left off.

 

Dean ran the flat of his tongue along the underside of Castiel’s cock, flicking his tongue into the slit. Castiel’s entire body twitched, and Cas again grabbed at Dean’s hair. Dean let Cas guide him as he took him into his mouth, sucking and working until Castiel was close to the brink. Dean pulled off, and looked up at Castiel, who was now braced on his elbows so that he could watch. A long string of spit dangled from Dean’s chin, and Cas used his index finger to gather the saliva and then sucked his own finger clean before pulling Dean up for a deep, sloppy kiss. Dean knew that Cas could taste himself on Dean’s lips and that realization had his own dick hard and leaking.

 

Cas ran his hands up and down Dean’s muscled arms as they sucked at each other’s tongues. Suddenly, Cas’s hands stilled, gripped, and Cas flipped them. He smirked down at Dean, and the heat in Dean’s stomach roiled when he saw a familiar glint in Cas’s eye. He wasn’t surprised when Cas put a finger into his mouth and ordered Dean to “suck.” Dean knew what was coming.

 

Castiel peppered his neck and chest with kisses as that saliva-soaked finger ghosted along Dean’s perineum. Dean was trembling with want before Castiel even breached his rim. “I got you,” Cas murmured. He withdrew his finger and reached for his backpack, rifling through its contents and fishing out a small bottle of lube.

 

Dean braced himself on his elbows and lifted an eyebrow quizzically. “You’re prepared. And here I was worried that you’d left me.”

 

Suddenly, Dean was flat on his back, a smitey-former-angel glaring down at him. “You thought I’d left?”

 

“Stupid, I know,” Dean admitted. He wrapped a leg around Castiel’s hips and pulled him close. “Can we forget I said that? Thought that?”

 

Castiel’s eyes narrowed. “That depends. Did you mean what you said – what _we_ said earlier?”

 

“Abso-fucking-lutely,” Dean affirmed. Cas rolled his eyes at Dean’s flippancy and started to draw away, but Dean clamped his hands on Castiel’s biceps. “No, Cas. For real, I meant it. I – um. I love you a lot, okay? It’s just… if you left, I don’t know what I’d do, who I’d be.” Dean blinked to clear his tear-filled eyes. “I need you, man.”

 

Castiel stared back at Dean for an unnervingly long moment before bending down and claiming Dean’s mouth in a kiss that left the younger man breathless. “I love you, Dean, but don’t ever underestimate me again,” he ordered.

 

“I promise, Cas. Really,” Dean said. He picked up the bottle that Cas had dropped and handed it back to him. “Now, can we get back to business?”

 

“You’re incorrigible,” Cas chided, flipping the top and covering his fingers with lube.

 

“Nah, I’m adorable,” Dean said, meeting Castiel’s smile with his own. They kissed long and deep, breathing quiet sentiments to each other, as Castiel slowly worked Dean open. By the time he was ready, both he and Cas were hard and leaking. Cas adjusted his hips and thrust his pelvis against Dean’s. The slip-slide of their cocks sent shockwaves of pleasure up Dean’s spine. Dean reached between them, and took both in hand, with Castiel’s hand quickly joining his, and together, they jacked themselves with strong, smooth strokes. In this moment, with Cas’s head bowed over him, their cocks pressed together, and Cas’s fingers inside him, Dean felt suspended from reality. His world narrowed to just him and Cas, bathed in moonlight and caressed by a cool evening wind. 

 

Castiel removed his fingers and pulled away before either could come. As if on cue, Dean shifted so that Cas could settle between his legs. He breathed a sign of relief when Castiel’s cock nudged against the aching emptiness left behind by agile fingers. Dean, his eyes squeezed shut, uttered a plaintive, “Cas – _please_.”

 

The pressure didn’t decrease, but Castiel didn’t press forward either. Fingertips graze his cheek. “Open your eyes,” Castiel murmured, so close that his breath caressed Dean’s skin.

 

Castiel was bowed over him, balancing himself with one hand flat on the ground beside Dean’s head. He held Dean’s gaze and carefully pushed inside. Impatient, Dean lifted his hips, forcing Castiel to bottom out quickly. Both gasped but didn’t break eye contact, even as they lay joined for a long moment.

 

Dean’s need to move crescendoed, but Castiel purposefully kept so still that sweat beaded his forehead. Dean reached up, tugging Cas closer, but instead of kissing him, Dean grazed his teeth lightly over the taut cords of Castiel’s neck. Cas shuddered, and Dean whispered in his ear. “Fuck me, Cas.” Castiel obliged, slowly moving in and out, a delicious drag of skin and lube. He kept his head down, shuddering each time Dean grazed and tongued whatever skin he could reach.

 

The tense lines of Castiel’s body betrayed the struggle to go slowly, and Dean _wanted_. He shifted again and tightened his legs around Castiel’s hips. Castiel moaned his name, and Dean tensed his muscles around Castiel’s cock, eliciting an inelegant yelp that left Dean smirking wickedly. “You want to play rough, Winchester?,” Castiel teased.

 

“Always,” Dean said, reaching for Castiel’s hands. Their fingers threaded together and with their hands braced on either side of Dean’s head, Castiel used that point of contact for balance as he began to thrust in earnest. They groaned in unison with each driving snap of Castiel’s hips, and Dean was not at all surprised when he wound up half on the grass, the sleeping bag bunched below him.

 

When this burning, building, all-encompassing _thing_ that they shared hit its zenith, Dean yelled Castiel’s name to the stars. Still hard, still thrusting, Castiel was close. His arms shook with effort, and Dean whispered, “Come for me, Cas,” as he clenched around Castiel. Cas came with a shout, his come flooding Dean’s insides with warmth, and they fell together, holding each other through the aftershocks.

 

When they were spent, Castiel cleaned them both off with his discarded tee shirt. He used his hands to brush off the grass stuck to Dean’s upper back, and then together, they opened the sleeping bag and spread it out.

 

Dean lay flat on his back, hands behind his head, looking up at the stars. He felt sated – happy even. As Castiel lay down beside him, mimicking his position, Dean thought about how far they had come to wind up here:  The Righteous Man and the Angel of the Lord that had rescued him from hell lying naked in a field of wildflowers and grasses.

 

Castiel’s voice broke Dean’s contemplation. “You know – from that moment, I was yours, too.”

 

Dean’s heart clenched, and he pulled his arms from under his head and reached for Castiel, who willingly tucked himself along Dean’s side. Dean draped the part of the sleeping bag that they weren’t lying on over them.

 

When the initial post-coital haze wore off, a pressing question returned to Dean’s mind.

 

“Hey, Cas? Where have you been sleeping?”

 

Cas, already half asleep against Dean’s chest muttered, “In _my_ room.”

 

“What? You have a room?”

 

Cas snorted. “Yes, Dean. I have a room.”

 

“Wait – so we’re not sharing anymore?”

 

Cas sighed. “Okay, so I _had_ a room. Now, watch the fireflies and let me sleep?”

 

Dean grinned and kissed Castiel’s temple. They lay entwined until the wee hours of the morning, bathed in moonlight, serenaded by nature’s nightly concert, and surrounded by twinkling fireflies.

 

+ 

**Author's Note:**

> My sincere apologies for posting to the challenge late! I haven't had a lot of writing time, and when I did, this story just didn't want to be written. I blame my lingering issues with S10 - it took forever to figure out how to bypass the Mark and the Darkness. I really hope the end result works for you! 
> 
> Thank you for reading!


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